This is a plugin for nagios to check network interfaces (network ports) on servers switches and routers. It is based on check_snmp_int.pl plugin by Patrick Ploy with extensive rewrites for performance improvements (caching improved execution time by up to 100%) and better support for Cisco switches (Cisco port names, port link and operational status data) and checking of STP (spanning tree protocol) status. Possibly most useful improvement is the ability to check port traffic & utilization without creation of temporary files.
Documentation for this plugin is contained within header of the perl code (several pages long). You can also do check_snmp_netint --help and will get fairly good overview and what options should be used.
In version 2.1 and above code that calculates bandwidth, link percent and other metric data has been changed to use average from more then one set of data (and plugin also now can return more then one historic set as part of performance data). This should result in smoother calculations and if you''re using this code then play with --pcount=? and --delta=? options trying values 1-4 for pcount and 50-1000 for delta (using --pcount=1 should be equivalent to old 2.0 code or how check_snmp_int plugin worked; --pcount=2 is the default for 2.1 and above code).
If you're using -P option to pass performance data back to plugin then you may (depending on version of nagios) also need to modify nagios.cfg and remove ' from illegal_macro_output_chars=`~$&|'" line, i.e. change to illegal_macro_output_chars=`~$&|".
